1. Field of the Invention
The invention relates to an integrated circuit configuration and to an ignition unit.
European Patent EP 0 471 871 B1 discloses an occupant protection system for motor vehicles in which a control unit disposed in a centralized manner in the motor vehicle controls, via a data bus, igniters disposed in an occupant protection device such as an airbag, a seat belt pretensioner, etc. Each igniter has a resistance heating wire that is embedded in an ignition material and is connected to an energy storage capacitor via a controllable power stage. A control circuit of the igniter receives messages communicated via the data bus and switches the power stage on in the event of an ignition command. With the result that the energy stored in the capacitor in the form of a current heats the resistance heating element and thus causes the ignition material to explode. The liberated energy in turn releases gas that is compressed in pellets and fills an airbag, for example.
Capacitors have been able to be integrated in silicon for a number of years. To date, however, the integrated capacitors have been distinguished by a relatively low capacitance. The applicant therefore proposed an integrated circuit configuration having a capacitor whose storage capacitance approaches that of conventional, discrete capacitors (see V. Lehmann et al., titled "A Novel Capacitor Technology Based On Porous Silicon" in Thin Solid Films, 276 (1996), Pages 138-142). In this case, pores are produced electrochemically in a semiconductor substrate--called a semiconductor layer below. The pores are covered with a dielectric layer and a polysilicon layer. The semiconductor layer and the polysilicon layer form capacitor electrodes. The capacitance of known integrated capacitors is significantly increased on account of the formation of pores.